Abstract

Nonnucleoside reverse transcriptase inhibitors (NNRTIs) have proven efficacy against human immunodeficiency virus type 1 (HIV-1). However, in the setting of incomplete viral suppression, efavirenz and nevirapine select for resistant viruses. The diarylpyrimidine etravirine has demonstrated durable efficacy for patients infected with NNRTI-resistant HIV-1. A screening strategy used to test NNRTI candidates from the same series as etravirine identified TMC278 (rilpivirine). TMC278 is an NNRTI showing subnanomolar 50% effective concentrations (EC50 values) against wild-type HIV-1 group M isolates (0.07 to 1.01 nM) and nanomolar EC50 values against group O isolates (2.88 to 8.45 nM). Sensitivity to TMC278 was not affected by the presence of most single NNRTI resistance-associated mutations (RAMs), including those at positions 100, 103, 106, 138, 179, 188, 190, 221, 230, and 236. The HIV-1 site-directed mutant with Y181C was sensitive to TMC278, whereas that with K101P or Y181I/V was resistant. In vitro, considerable cross-resistance between TMC278 and etravirine was observed. Sensitivity to TMC278 was observed for 62% of efavirenz- and/or nevirapine-resistant HIV-1 recombinant clinical isolates. TMC278 inhibited viral replication at concentrations at which first-generation NNRTIs could not suppress replication. The rates of selection of TMC278-resistant strains were comparable among HIV-1 group M subtypes. NNRTI RAMs emerging in HIV-1 under selective pressure from TMC278 included combinations of V90I, L100I, K101E, V106A/I, V108I, E138G/K/Q/R, V179F/I, Y181C/I, V189I, G190E, H221Y, F227C, and M230I/L. E138R was identified as a new NNRTI RAM. These in vitro analyses demonstrate that TMC278 is a potent next-generation NNRTI, with a high genetic barrier to resistance development.

Chemical structure and 3-dimensional model of TMC278. The chemical structure of TMC278, C22H18N6, or 4-[[4-[[4-[(1E)-2-cyanoethenyl]-2,6-dimethylphenyl]amino]-2-pyrimidinyl]amino]benzonitrile, is shown. Red represents CN groups or the nitrogen of the pyrimidine and the nitrogen of the aniline (highest density of charge in the structure), and blue represents the aromatic group (no charge).

Effect of the time of addition of TMC278 on its anti-HIV-1 activity compared with that of other ARVs. The antiviral activity of TMC278 was determined at various times of addition of the compound in order to estimate the viral replication stage at which TMC278 inhibits the HIV-1 replication cycle by using the known ARV inhibitors BMS-806, AMD-3100, ENF, and EFV as references.

Selection of viruses resistant to TMC278, ETR, EFV, or NVP starting from wild-type HIV-1 IIIB. The time to breakthrough of resistant viruses was determined in cell culture, over a 32-day period, under selective pressure from various concentrations of TMC278, ETR, EFV, and NVP, or in the absence of NNRTIs (control).

Selection of viruses resistant to TMC278, EFV, ETR, or NVP, starting from recombinant viral strains containing the NNRTI RAM K103N (A) or Y181C (B). The time to breakthrough of resistant viruses was determined in cell culture, over a 32-day period, under selective pressure from various TMC278 concentrations.